1. Field of the Invention
The present invention relates to a method and apparatus for rehabilitation of neuromotor disorders such as improving hand function, in which a system provides virtual reality rehabilitation exercises with index of difficulty determined by the performance of a user (patient).
2. Description of the Related Art
The American Stroke Association states that stroke is the third leading cause of death in the United States and a major cause for serious, long-term disabilities. Statistics show that there are more than four million stroke survivors living today in the US alone, with 500,000 new cases being added each year. Impairments such as muscle weakness, loss of range of motion, decreased reaction times and disordered movement organization create deficits in motor control, which affect the patient""s independent living.
Prior art therapeutic devices involve the use of objects which can be squeezed such as balls which are held in the patient""s hand and the patient is instructed to apply increasing pressure on the surface of the ball. This device provides for resistance of the fingers closing relative to the palm, but has the limitation of not providing for exercise of finger extensions and finger movement relative to the plane of the palm and does not provide for capturing feedback from the patient""s performance online.
It has been described that intensive and repetitive training can be used to modify neural organization and recover functional motor skills For post-stroke patients in the chronic phase. See for example, Jenkins, W. and M. Merzenich, xe2x80x9cReorganization of Neocortical Representations After Brain Injury: A Neurophysiological Model of the Bases of Recovery From Stroke,xe2x80x9d in Progress in Brain, F. Seil, E. Herbert and B. Carlson, Editors, Elsevier, 1987; Kopp, Kunkel, Muehlnickel, Villinger, Taub and Flor, xe2x80x9cPlasticity in the Motor System Related to Therapy-induced Improvement of Movement After Stroke,xe2x80x9d Neuroreport, 10(4), pp. 807-10, Mar. 17, 1999; Nudo, R. J., xe2x80x9cNeural Substrates for the Effects of Rehabilitative Training on Motor Recovery After Ischemic Infarction,xe2x80x9d Science, 272: pp. 1791-1794, 1996; and Taub, E. et al., xe2x80x9cTechnique to Improve Chronic Motor Deficit After Stroke,xe2x80x9d Arch Phys Med Rehab, 1993, 74: pp. 347-354.
When traditional therapy is provided in a hospital or rehabilitation center, the patient is usually seen for half-hour sessions, once or twice a day. This is decreased to once or twice a week in outpatient therapy. Typically, 42 days pass from the time of hospital admission to discharge from the rehabilitation center, as described in P. Rijken and J. Dekker, xe2x80x9cClinical Experience of Rehabilitation Therapists with Chronic Diseases: A Quantitative Approach,xe2x80x9d Clin. Rehab, vol. 12, no. 2, pp. 143-150, 1998. Accordingly, in this service-delivery model, it is difficult to provide the amount or intensity of practice needed to effect neural and functional changes. Furthermore, little is done for the millions of stroke survivors in the chronic phase, who face a lifetime of disabilities.
Rehabilitation of body parts in a virtual environment has been described. U.S. Pat. No. 5,429,140 issued to one of the inventors of the present invention teaches applying force feedback to the hand and other articulated joints in response to a user (patient) manipulating an virtual object. Such force feedback may be produced by an actuator system for a portable master support (glove) such as that taught in U.S. Pat. No. 5,354,162 issued to one of the inventors on this application. In addition, U.S. Pat. No. 6,162,189 issued to one of the inventors of the present invention, describes virtual reality simulation of exercises for rehabilitating a user""s ankle with a robotic platform having six degrees of freedom.
The invention relates to a method and system for individually exercising one or more parameters of hand movement such as range, speed, fractionation and strength in a virtual reality environment and for providing performance-based interaction with the user (patient) to increase user motivation while exercising. The present invention can be used for rehabilitation of patients with neuromotor disorders, such as a stroke. A first input device senses position of digits of the hand of the user while the user is performing an exercise by interacting with a virtual image. A second input device provides force feedback to the user and measures position of the digits of the hand while the user is performing an exercise by interacting with a virtual image. The virtual images are updated based on targets determined for the user""s performance in order to provide harder or easier exercises. Accordingly, no matter how limited a user""s movement is, if the user performance falls within a determined parameter range the user can pass the exercise trial and the difficulty level can be gradually increased. Force feedback is also applied based on the user""s performance, and its profile is based on the same targeting algorithm.
The data of the user""s performance can be stored and reviewed by a therapist. In one embodiment, the rehabilitation system is distributed between a rehabilitation site, a data storage site and a data access site through an Internet connection between the sites. The virtual reality simulations provide an engaging environment that can help a therapist to provide an amount or intensity of exercises needed to effect neural and functional changes in the patient. The invention will be more fully described by reference to the following drawings.
In a further embodiment, the data access site includes software that allows the doctor/therapist to monitor the exercises performed by the patient in real time using a graphical image of the patient""s hand.